Most of the conventional type fruit assorting instruments in present use are provided with a plurality of cylinders having diametrally different throughholes on circumferentially suitable surface thereof disposed in parallel, starting with a cylinder having the smallest diameter holes and ending with a cylinder having the largest diameter holes, wherein spherical fruits to be assorted are conveyed on the rotating cylinders and permitted to fall down through the holes onto a moving conveyor belt provided internally of each clyinder.
There is another type of fruit assorting instrusment wherein a plurality of supporting elements are disposed on plane surface to form thereon assorting holes so disposed that when fruits to be assorted are being conveyed on the plane surface, said holes are diametrally enlarged in succession by winding the supporting elements, whereby the fruits are permitted to pass through the holes to each different position in sequence of size.
Referring to the foregoing cylinder type fruit assorting instruments, however, they are disadvantageous in that fruits to be assorted must be repeatedly rolled directly on the moving cylinders so that, the larger the fruits are, the more often they are forced to roll along the cylinders on the midway before reaching the last cylinder, resulting in the fruits being excessively damaged. Further referring to the plane surface type fruit assorting instrument, it has great disadvantages in that it is quite complicated in structure and expensive to manufacture and further characterized by difficulty in predetermining the diameter of the assorting holes.